Estimation of a CME magnetic field strength using observations of gyrosynchrotron radiation
by E. P. Carley et al.*

2018-01-09 378 views

Despite many years of study, the dominant driver and energy source of coronal mass ejections (CMEs) is still under investigation. Observational studies have indicated that magnetic energy represents the largest part of the total energy budget of the eruption (Emslie et al., 2012, Carley et al., 2012). However, despite having such a dominant influence on CME dynamics, little is known about CME magnetic field. This is due to the scarcity […]

Propagation and Interaction Properties of Successive Coronal Mass Ejections in Relation to a Complex Type II Radio Burst
by Y. D. Liu et al.*

2017-12-19 598 views

Quantifying how coronal mass ejections (CMEs), particularly fast ones, propagate from the Sun to the Earth is an overarching issue in CME research and space weather forecasting. A typical fast CME would finish its major deceleration well before reaching 1 AU (Liu et al. 2013). The actual situation of CME Sun-to-Earth propagation, however, may involve interactions with the highly structured solar wind including other CMEs. Interactions involving more than two […]

Critical Fluctuations in Beam-Plasma Systems and Solar Type III Radio Bursts
by G. Thejappa and R. J. MacDowall

2017-12-05 476 views

The type III radio bursts are the most intense radio emissions from the sun. In Figure 1, we present a typical type III burst observed by the STEREO spacecraft. Ginzburg and Zheleznyakov (1958) were the first to suggest that Langmuir waves excited by the solar flare accelerated electrons are the source of these bursts. The in situ detection of electron beams and Langmuir waves in association with type III bursts […]

Observations of solar radio burst fine structures with LOFAR
by E. Kontar et al.*

2017-11-28 1,148 views

During solar flares, electrons are accelerated up to relativistic speeds. As they propagate upwards through the solar corona, they produce so-called type III radio bursts. These type III bursts often demonstrate fine structure, with their spectra consisting of multiple narrowband “striae”; most likely, these structures are caused by small-scale density inhomogeneities of the coronal plasma so that the subsequent fundamental plasma processes that produce the radio bursts is produced in […]

VLA Measurements of Faraday Rotation through Coronal Mass Ejections
by Jason E. Kooi et al*

2017-11-21 368 views

Coronal mass ejections (CMEs) are large-scale eruptions of ionized gas (or plasma) from the Sun. The ejected material of a CME is associated with strong magnetic fields, which can cause substantial geomagnetic storms at Earth that enhance the radiation space environment and affect global communications and geolocation. Remote-sensing techniques such as Faraday rotation (FR), the rotation of the plane of polarization of linearly polarized radiation as it propagates through a […]

Solar Prominence Modelling at ALMA Wavelengths
by A. Rodger and N. Labrosse

2017-11-14 427 views

The small-scale temperature structure of prominences remains an outstanding question in solar physics. Theoretical models provide scenarios for how cool prominence plasma can be formed and maintained within the extreme conditions of the corona. However, knowledge of the detailed temperature structure of the prominence plasma and its evolution at small spatial and temporal scales is still lacking. The Atacama Large Millimeter/sub-millimeter Array (ALMA) provides a novel method for high spatial […]

Small electron acceleration episodes in the solar corona
by T. James et al.

2017-11-07 674 views

Large solar flares are well known sites of prodigious particle acceleration. While these have deservedly attracted considerable attention, small episodes of electron acceleration and heating have been lately recognized as possible candidates for heating the quiet solar corona. We study the number, power and energy carried by nonthermal electrons produced by instances of small scale electron acceleration in the solar corona. Our primary focus is on small electron acceleration events […]

Acceleration and Storage of Energetic Electrons in Magnetic Loops in the Course of Electric Current Oscillations
by V.V. Zaitsev and A.V. Stepanov

2017-10-31 534 views

There are long-lived radio events on the Sun and stars like in type IV solar radio bursts with sudden reductions and pulsating type III bursts (Slottje, 1972; Huang et al. 2016) as well as intriguing intense radio emission from ultracool stars that lasts for several rotation periods (Hallinan et al. 2007). This can be the result of the multiple injections of accelerated electrons into the coronal magnetic loops. The idea […]

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